[Inequalities in COVID-19 mortality in Argentina's northern international border. Space-time analysis]

The COVID-19 pandemic exposed inequalities in mortality across territories. Northern Argentina, characterized by high social vulnerability and active international borders, despite formal closures, may have favored the spread of the virus.

To identify high-mortality clusters (HMC) due to COVID-19 among older adults (≥60 years) between 2020-2022, in relation to socioeconomic conditions and the border strip (FF).

A population-based ecological study of COVID-19 deaths was conducted in provinces with international border strips. Spatial and space-time scan analyses were applied to detect highmortality clusters (HMC). The relationship between these clusters, socioeconomic indicators, and location within the border strip was evaluated.

Between 2020 and 2022, 12 968 deaths were recorded among older adults. In 2020, HMC were located in Salta and Jujuy (RR=3.6). In 2021, clusters shifted to Chaco and Formosa, in areas bordering Paraguay. In 2022, they concentrated in Corrientes and Misiones (RR=1.6-1.8). Population density was associated with clusters in 2020. Over the entire period, 41% of HMC were located within the FF.

In 2020, the departments connected to Bolivia through road corridors showed higher mortality, and the expansion observed in 2021 coincided with the increase in deaths in Paraguay. Several studies have reported the persistence of informal or illegal border crossings, which may have sustained active cross-border circulation. These findings highlight the importance of regional cooperation and the need to strengthen epidemiological surveillance in border areas.